Immune responses to SARS-CoV-2 infection in Humans and ACE2 humanized mice

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) represents a major public health threat worldwide. Insight into protective and pathogenic aspects of SARS-CoV-2 immune responses is critical to work out effective therapeutics and develop vaccines for controlling the disease. Here, we review the present literature describing the innate and adaptive immune responses including innate immune cells, cytokine responses, antibody responses and T cell responses against SARS-CoV-2 in human infection, as well as in AEC2-humanized mouse infection. We also summarize the now known and unknown about the role of the SARS-CoV-2 immune responses. By better understanding the mechanisms that drive the immune responses, we can tailor treatment strategies at specific disease stages and improve our response to this worldwide public health threat.